Electronic sensor systems have found their way into products that are under air-pressure, like air-springs. In most cases this requires an electrical connection from the outside of the air-tight container to the inside and/or vice versa. These connections are typically used for providing electric power and/or control signals to electric elements and/or actuators housed within the air spring or for transmitting signals from any kind of sensors housed within the air-spring to a monitoring and/or control unit housed outside of the air spring.
Sophisticated air-springs can now be purchased with a height sensor system integrated. In addition, air-springs are on offer with an integrated accelerometer, air-pressure sensor, and temperature sensor, for example. Typically, these air-springs (with integrated sensor-actuator functions) can be referred to as smart air-springs.
A typical air-spring is an elastic and tubal shaped member (also called rubber sleeve), that is sealed air-tight by round shaped lids that close-off the top and the bottom of the sleeve. The bottom lid is called “piston” and is movable with respect to the top lid during operation of the air spring.
Electronic sensor systems are mounted from the inside of the air-spring onto the upper lid or into the bottom piston. The wire connection to the outside world (that connects the air-spring integrated electronics with the air-spring outside world) is then done through a hole that has to be tooled into either the top plate or the piston device of the air-spring. If not sealed in some ways, the compressed air inside the air-spring would escape through this hole.
Typically, some effort has to be spent for isolating the electrical feed-through from the interior of the air spring housing to the exterior though the known existing solutions may not provide satisfying isolation.
Some air-tight connectors have used molten glass to create an insulated and semi-air-tight connection between the individual metal pins (electric connectors) and the housing of the connector itself. The disadvantage of this professional solution is the relative high price and that such connectors need a relative large space to be fitted correctly.